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The Growth and Rubber Content of Guayule as Affected by Variations in Soil Moisture Stresses 1
Author(s) -
Hunter Albert S.,
Kelley Omer J.
Publication year - 1946
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1946.00021962003800020003x
Subject(s) - soil water , citation , agriculture , water content , mathematics , agricultural economics , library science , environmental science , horticulture , archaeology , geography , engineering , soil science , economics , computer science , geotechnical engineering , biology
GUAYULE, Parthenium argentatum Gray, is a rubber-producing shrub, native to certain sections of the Chihuahuan desert. For about 30 years previous to 1942 it was grown domestically on a comparatively small scale in California and the Southwest by private concerns. In 1942 all private holdings within the United States were purchased by the government and a greatly expanded production program was initiated under the direction of the Emergency Rubber Project, an agency of the Forest Service of the Department of Agriculture. Concurrently, an extensive research program was initiated by the Special Guayule Research Project of the Bureau of Plant Industry, Soils, and Agricultural Engineering. Since the domestic production of guayule began, occasional generalized. statements regarding the effects of irrigation upon its growth and rubber content have appeared in the semi-technical and popular literature; however, almost no experimental evidence on this matter has been published until very recently. Lloyd (5) a in his technical monograph in 191I suggested that a trial should be made of growing the shrub under irrigation for two or three years and then subjecting it to a period of drought before harvest. The Intercontinental Rubber Company conducted experiments on the irrigation of guayule, but the records of their studies are to be found only in the Company’s private files. Their investigations indicated that in most cases irrigations up to and including the final year of harvest increased the yield of rubber on the per acre basis. Kelley, Hunter, and Hobbs (3), in study of the effects of soil moisture stresses on guayule nursery stock, found that the dry weight production increased with increasing sup.plies of soil moisture but that the concentration of rubber and resin of the plants decreased at the same time. The field experiments on guayule irrigation that are reported herewith were set up in 1944, jointly by the soils division and the pathology division of the Special Guayule Research Project, and the Emergency Rubber Project. 4 These experiments were conducted to study the effects of a wide range of soil moisture stresses, from very high to very low, on both a light soil and a heavy soil, upon (a) the growth and the rubber and resin formation of guayule and upon (b) guayule diseases.